Vacuum pump and arrangement with vacuum pump

ABSTRACT

A vacuum pump includes a housing having an axial inlet a pumping unit including a stator, a rotor rotatably supported in the stator, and a drive for driving the rotor. At least one housing part which has at least one outlet, is placed on the housing in an axial direction and is connected with the housing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vacuum pump and an arrangement with a vacuum pump.

2. Description of the Prior Art

Vacuum pumps, in particular turbomolecular pumps have at least one rotor that is arranged in the pump housing. The rotor is surrounded by a stator package or several stators which are supported in the housing. Further, a drive, e.g., an electric motor that drives the at least one rotor, is also arranged in the pump housing. Usually, the drive shaft is arranged coaxially with the rotor axis.

With the turbomolecular pumps, high compression ratios can be achieved. The turbomolecular pumps have a very small outlet opening or outlet nipple in comparison with an inlet opening or inlet nipple. Usually, a conduit connects a forevacuum pump with the outlet nipple.

Arrangements which include vacuum pumps and recipients, which further refer to as chambers, present a number of requirements, with regard to their geometrical design. E.g., with mass-spectrometers, it is desirable that the entire system has compact dimensions. Often, this results in such positioning of the vacuum pump in the end apparatus that its access is noticeably limited. Despite this, the servicing of the vacuum pump, e.g., preventive replacement of shaft bearings, should be possible.

According to the state of the art (EP 2 228 540 A2), there is provided an arrangement with a vacuum pump having a pump flange. The arrangement also has a chamber flange and flange connecting means for vacuum-tight connection of the chamber and the vacuum pump. The arrangement also includes a force transmitting structure for transmitting force from an application point to an operating point located in the flange connection means.

This means that the vacuum pump is usually arranged in a receiver provided in the arrangement to this end. The receiver can be formed as some type of a rail system. The pump flange and the chamber flange are vacuum-tightly connected with each other. Here, the inlet openings of the pump are so arranged that they are aligned with outlet openings of the chamber, overlaying each other. This state-of-the art pump can be easily extracted from the arrangement after loosening respective connection and connection means, e.g., to effect a preventive replacement of shaft bearings.

These state-of-the art arrangements should meet customer-specific requirements with regard to position of the chamber outlets and the geometry of the pump receiver.

In a system with several suction openings for different pressure levels, as known in practice, several separate pumps are used. In particular, with mass-spectrometers with time-of-flight systems, the increased distances between different suction openings are observed. The time-of-flight mass-spectrometers form a sub-class of mass-spectrometers.

In practice, with the time-of-flight mass-spectrometers, so-called split-flow pumps are used. Split-flow pumps represent vacuum pump systems for multi-stage gas inlet systems disclosed, e.g., in DE 43 31 589 A1.

These state-of-the art split-flow pumps usually have a constructional length of 500 mm. If, however, the suction openings are spaced by a large distance, as it is known from practice, the pump houses, which are long enough to bridge large distances between the suction openings, can be produced only with very expensive machine-tools.

The object of the invention is to so improve the state-of-the art vacuum pumps and arrangements with vacuum pumps that the customer-specific requirement can be realized in a simpler and more cost-effective manner, and that cheaper vacuum pumps with a large length are produced.

SUMMARY OF THE INVENTION

The object of the invention is achieved with a vacuum pump including a housing having an axial inlet a pumping unit including a stator, a rotor rotatably supported in the stator, and a drive for driving the rotor, and at least one additional placed-on housing part attachable to the housing in an axial direction, connectable with the housing, and having at least one outlet.

The advantage of the inventive vacuum pump consists in that with the additional housing part placed on in the axial direction, a greater constructional length of the vacuum pump which is often required in the field, can be realized. In addition, a standard vacuum pump can be used, and the placed-on housing part then is provided with dimensions capable to meet customer-specific requirements.

In addition, the vacuum pumps can be formed with through-housings having greater lengths then it was possible with tools known up to now. Namely, the state-of-the art machine-tools limit the constructional length of the housing.

With the provision of at least one additional housing part, in principle, any arbitrary length can be provided.

The placed-on housing part has an advantage, in comparison with, e.g., attached tube, that consists in that the diameter and the outer profile of the housing are formed so that they remain the same as for the entire vacuum pump, so that flanges, openings, rail system and the like of the inventive pump can be used in arrangements, e.g., including a mass-spectrometer.

In addition the placed-on tubes often have a bent-off section in order to be able to connect the tube with an outlet of a pump chamber arranged radially with respect to the longitudinal axis of the pump. Because of the bent-off section, a state-of-the art vacuum pump with a placed-on tube cannot be received in existing receivers.

According to a particular advantageous embodiment of the invention, the at least one placed-on part has at least one radial inlet.

This radial inlet serves for connection, with an outlet of a pumped chamber of the arrangement in which the vacuum pump is arranged.

If the arrangement has several chambers, advantageously, the placed-on part has a corresponding number of inlets which overlay respective outlets of the chambers.

According to a further advantageous embodiment of the invention, the at least one radial inlet of the placed-on housing part is provided at the end of the placed-on housing part remote from the drive.

Arrangements with mass-spectrometers having time-of flight systems often have increased distances between different suction openings. Because in the placed-on housing part, customer-specific radial inlets can be formed, it is advantageous when at least one radial inlet or the last radial inlet is provided at the end remote from the drive, i.e., at the end of the housing part remote from the pump-active structures.

According to a further advantageous embodiment of the invention, the housing of the vacuum pump has at least one radial inlet. This means that the vacuum pump itself has at least one radial inlet provided in the housing to which the additional housing part is attached.

According to a further advantageous embodiment of the invention, the at least one placed-on housing part has an outer profile at least partially similar to that of the housing. Thereby, it is insured that the vacuum pump housing and the placed-on housing part have an outer profile of a one-piece housing. Thereby, it becomes possible to particularly advantageously arrange the vacuum pump in a receiver of an arrangement with mass-spectrometer.

Identical outer profiles of a housing and a placed-on housing part can advantageously be interrupted by a necking.

According to yet another advantageous embodiment of the invention, pump-active structures of the vacuum pump can at least partially be located in the placed-on housing part. There also exists a possibility to arrange a bearing star for a rotor bearing in the placed-on housing part.

Other components likewise can be provided in the housing part.

According to another embodiment of the invention, no pump-active structures of the vacuum pump are arranged in the placed-on housing part. In this case, the at least one placed-on housing part forms a pure extension of the vacuum pump housing.

The housing and at least one placed-on housing part have advantageously a total length of at least 550 mm. Vacuum pump housings with a length less than 500 mm can be manufactured with usual expenses by conventional machine-tools.

The invention, advantageously, permits to achieve lengths of more than 550 mm, e.g., lengths of more than 700 mm can be practically obtained.

According to yet further advantageous embodiment of the invention, the inlet openings of the housing and the outlet openings of the placed-on housing part are so formed that they overlay each other. Thereby, it is insured that the placed-on housing part functions as an extension of the vacuum pump housing.

According to a still further embodiment of the invention, two placed-on housing parts placed one onto the other can be provided, with the outer opening of the second housing part overlaying the inlet opening of the first housing part, whereby a further extension of the vacuum pump housing becomes possible.

According to another particularly advantageous embodiment of the invention, at least one thermally isolating sealing element, and/or vibration-isolating sealing element, and/or electrically isolating sealing element is provided between the housing of the vacuum pump and the placed-on housing part, and/or between two placed-on housing parts when two housing parts are placed one upon the other. This function can be incorporated in a particularly formed sealing element.

This embodiment permits, e.g., to achieve a thermal separation of housing parts. Also, electrical isolation and/or vibration-isolation also become possible.

According to an advantageous embodiment of the invention, the vacuum pump is formed as a turbomolecular pump.

However, it is also possible to provide other types of pumps with the inventive housing extension.

According to another embodiment, the vacuum pumps can be formed with two gas inlets. This type of pumps is called split-flow pumps. This type of pumps are often used in arrangements with multi-stage gas inlet system, e.g., with mass-spectrometers. It is particularly in this arrangements, it is often desirable to have housings adapted to customer-specific requirements.

The vacuum pump can have, e.g., at least one turbomolecular pump stage and/or at least one Holweck pump stage. The at least one Holweck pump stage usually is arranged downstream of the at least one turbomolecular pump stage in the gas flow direction. The gas inlets are advantageously arranged in front of, between, or behind the turbomolecular pump stages and/or Holweck pump stages.

An inventive arrangement comprises a vacuum pump including a housing having an axial inlet, a pumping unit having a stator, a rotor rotatably supported in the stator, and a drive for driving the rotor, and a pump flange; a chamber having a chamber flange; means for vacuum-tightly connecting the vacuum pump and the chamber and including both the pump flange and the chamber flange; with the vacuum pump further including at least one additional placed-on housing part attachable to the housing in an axial direction, connectable with the housing, and having at least one outlet and at least one radial inlet connectable with the chamber.

With this embodiment of the arrangement that includes a vacuum pump, the vacuum pump can be used in an arrangement with several suction openings spaced from each other, without particularly high machining and finishing costs in housing manufacturing.

According to a particularly advantageous embodiment of the invention, the arrangement has a force-transmitting structure for transmitting force from an application point to at least one operating point provided on the connecting means. This force-transmitting structure is disclosed in EP 2 228 540 A2.

As discussed, the inventive arrangements are particular advantageous when used with mass-spectrometers because in these arrangements several gas inlets are available which, under circumstances, can form suction openings spaced from each other by large distances.

According to a yet particularly advantageous embodiment of the invention, the housing of the vacuum pump and the at least one placed-on housing part have an outer profile adapted to a receiver provided in the arrangement. Thereby, it became possible to fit the vacuum pump with the placed-on housing part in an available structure of the arrangement. The arrangement receivers for vacuum pump housing are so formed that they are adapted to the outer profile of the vacuum pump housings. In this case, it is advantageous when the placed-on housing part has the same outer profiled to insure fitting of the housing with the placed-on housing part in the receiver.

Basically, there exists also a possibility that the placed-on housing part is offset relative to the vacuum pump housing. This embodiment is formed in response to corresponding requirements specified by the customer.

Because of the tolerances of separate housing parts and form and position deviations of the housings and the at least one housing part during the fitting process, it is advantageous to provide the bearing of the high vacuum side in the vacuum pump housing. In this case, the tolerances of the placed-on housing part can be greater.

Advantageously, the inventive pump is secured in the arrangement with a rail system. The rail system enables mounting and dismounting of the vacuum pump from one side by axial push-in or pull-out, as described in EP 2 228 540 A2. The pump access then must be provided only from one side for carrying out mounting and dismounting, whereby the system can be compactly formed, e.g., with smaller costs of the pump or the pump replacement.

Advantageously, the regions between the sealing planes are formed complementary to each other so that the housing is not subjected to pressure or non-acceptably deformed because of crowning and like position errors.

By greater spacing of the radial suction openings in the placed-on housing part with respect to the housing, it became possible to subject, in particular, the high vacuum region of the pump to high temperatures. The large surface and the length of the at least one placed-on housing part positively influence the temperature behavior of the pump.

Due to use of several parts, it became possible, in addition, to realize a thermal separation of the housing part or parts from the vacuum pump housing. This can be carried out by reduction of the contact surfaces or by using isolating intermediate elements or sealing elements. An electrical isolation or vibration isolation can also be realized.

The invention made possible a modular construction, with the vacuum pump housing forming a base of the pump with different housing extensions, i.e., with placed-on housing parts having different lengths. It is also possible to provide the base pump with a cover instead of an extension.

The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings which show several exemplary embodiments of the inventive vacuum system.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings show:

FIG. 1 a longitudinal cross-sectional view of a vacuum pump with a total of three inlets;

FIG. 2 a longitudinal cross-sectional view of a vacuum pump with a total of two inlets;

FIG. 3 a longitudinal cross-sectional view of a vacuum pump without pump-active structures;

FIG. 4 a perspective view of a vacuum pump;

FIG. 5 a longitudinal cross-sectional view of a connection between a housing and a housing part;

FIG. 6 a longitudinal cross-sectional view of a connection between a housing and a housing part according to another embodiment of the present invention;

FIG. 7 a longitudinal cross-sectional view of a connection between a housing and a housing part according to yet another embodiment of the present invention;

FIG. 8 a cross-sectional view of a screw connection between a housing and a housing part;

FIG. 9 a cross-sectional view of an arrangement with chambers and a vacuum pump that represents an integrated system;

FIG. 10 a cross-sectional view of a flange connection along line I-I′ in FIG. 9; and

FIG. 11 a cross-sectional view of a flange connection along line II-II′ in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a vacuum pump 1 having a housing 2. The vacuum pump 1 has a rotor 3 carrying rotor vanes 4. The rotor vanes 4 alternate with stator vanes 5 and form different vacuum pump stages of the pump 1.

At the high-vacuum side, the rotor 3 is supported by a bearing star 6. For the sake of clarity the bearing is not shown. At the forevacuum side, the rotor 3 is likewise supported by bearings, e.g., ball bearings.

The housing 2 of the vacuum pump has an axial inlet 7. In addition, there are provided two radial inlets 8 and 9.

On the housing 2, an additional housing part 10 is arranged having a further radial inlet 11. The housing part 10 has the same cross-section and the same outer profile as the housing 2. An outlet 12 of the housing part is so formed that it completely overlays the inlet 7 of the housing 2.

In addition, the housing 2 has a radial outlet 13 that can be connected with a forevacuum pump (not shown).

The pump-active structures of the rotor 3, the rotor vanes 4, the stator vanes 5, the bearing star 6 are completely arranged in the housing 2 according to FIG. 1. The placed-on housing part forms an extension of the housing 2. With this arrangement, it is possible to achieve a total length L of the housing 2 and the placed-on housing part 10 of at least 550 mm, advantageously of at least 700 mm. Thereby, it becomes possible to remove the suction opening 11 (inlet 11) relatively far from the suction openings 8, 9 (inlets 8, 9), without a need to manufacture the housing 2 with expensive machine-tools when the housing is formed as a one-piece member.

An interface 19 is provided between the housing 2 and the housing part 10, as discussed with reference to FIGS. 5 through 8.

FIG. 2 likewise shows a vacuum pump 1 with a housing 2 and a housing part 10.

The same components are designated with the same reference numerals and would not be precisely described again. According to this embodiment, the housing 2 has only one radial inlet 9.

The placed-on housing part 10 increases the length of the housing 2 so that the combined length of the housing 2 and the placed-on component 10 is almost twice of the length of the housing 2.

As shown in FIG. 2, a portion of the pump-active structures is located in the placed-on housing part 10. Thus, e.g., the bearing star 6 and the high-vacuum pump stage are located in the housing part 10.

FIG. 3 shows a further vacuum pump 1 without any pump-active structures in the housing 2. The housing 2 has inlets 8, 9 and a radial outlet 13. The housing part 10 has a radial inlet 11. In addition, the housing 2 has a necking 14 in order to reduce the heat flow from high vacuum to the rotor or the housing 2.

FIG. 4 shows a vacuum pump 1 with a housing 2 and the placed-on housing part as well as with the inlets 8, 9 and 11. As shown in FIG. 4 the housing 2 and the housing part 10 have the same outer profile. E.g., cooling ribs 15 of the housing 2 continue as cooling ribs 16 of the housing part 10. A necking 14 is also clearly shown in FIG. 4. In addition, on the housing 2 and the housing part 10, there are provided strips 17, 18 which insure an additional stabilization of the housing 2 and the housing part 10 relative to each other and over the entire length of the vacuum pump 1.

The connection of the housing 2 and the housing part 10 is effected over an interface 19. According to FIG. 5, in the interface 19, there is provided an O-ring seal 20 to achieve a vacuum-tight connection of the housing 2 with the housing part 10.

According to FIG. 6, the interface 19 has, in addition to the O-ring seal 20, a sealing element 21. The sealing element 20 can be formed as a thermal, and/or vibration-isolating, and/or electrical sealing element.

FIG. 7 shows an interface 19 with the O-ring seal 20 and a sealing element 22 which is likewise formed as a thermal, and/or vibration-isolating, and/or electrical sealing element.

FIG. 8 shows a screw connection of the housing 2 and the housing part 10. The screw connection serves for a vacuum-tight and mechanical connection of the housing 2 and the housing part 10. The screw connection consists of a screw 25, a washer 26, and an elastomeric member 24 for vibration isolation. A sleeve 23 is provided as a force-transmitting element.

FIG. 9 shows the arrangement of a vacuum pump 1 in a system including a vacuum pump 1 and a chamber 102.

The chamber 102 is formed as a multi-chamber system for operating with different pumps and has, to that end, a forevacuum chamber 121, an intermediate chamber 122, another intermediate chamber 123, and a high-vacuum chamber 166. These chambers are connected with each other by openings 125, 126, 127 through which, e.g., a stream of gas particles flows. In the high vacuum chamber 166, there is provided a detector, e.g., a mass-spectrometer 124 which is controlled by a control packaged circuit 136. The chamber 102 has a chamber flange 120 with which the pump flange 110 is connected.

The pump flange 110 forms part of the vacuum pump 1 which also includes a shaft 111 which is rotatably supported, at its high-vacuum side, by a bearing 113, e.g., by a permanent magnet bearing. The shaft 111 is rotated by drive 114 so that in the pump stages 115, 116, compression and suction take place.

A suction opening 127 connects the inlet of the pump stage 115 with the intermediate chamber 122. The suction opening 128 connects the pump stage 116 with the intermediate chamber 123. The suction opening 169 connects the pump stage 168 with the high-vacuum chamber 166.

The gas enters the vacuum pump 1 through the suction opening 169, is compressed in the pump stage 168 and then is compressed, together with the gas entering the vacuum pump 1 through the suction opening 128, in the pump stage 116. A further compression, together with the gas flowing from the intermediate chamber 122 into the vacuum pump 1 through the suction opening 127, takes place in the pump stage 115. The outlets of the vacuum pump 1 and the forevacuum chamber 121 are connected by a vacuum conduit 141 with a forevacuum pump 140 which further compresses the gas and discharges it against the atmosphere. The pump stages 115, 116, and 168, advantageously, are formed as turbomolecular pump stages.

The vacuum pump 1 and the chamber 102 are arranged in a stand 130. The vacuum pump 1 is connected with the vacuum-tight chamber by a flange connection, i.e., via the chamber flange and the pump flange. The stand 130 also carries the control packaged circuit 136 of the mass-spectrometer and further components 133, 134, 135, e.g., network elements, calculation unit, and the like. The frame 130 is covered with lining 131. The vacuum pump 1 and the chamber 102 are accessible through a hinged lid 132, but other components, however, are surrounded by the stand 130. The flange connection is, therefore, accessible with much difficulty and only from the side adjacent to the hinged lid 132. Mounting and dismounting of the vacuum pump is only possible from the lid side.

The vacuum pump 1 has a housing 2 and a placed-on housing part 10. The placed-on housing part 10 has the inlet 11 connected with the suction opening 169. With the placed-on housing part 10, the vacuum pump has an increased length made possible by the arrangement shown in FIG. 9.

The mounting without problems is made possible by a force-transmitting structure according to FIGS. 10 and 11.

FIG. 10 shows a cross-sectional view of a force-transmitting structure 165 transverse to the shaft 111 along line I-I′ in FIG. 9. The chamber flange 120 and the pump flange 110 are in contact with each other. For providing a vacuum-tight connection, a seal 119 that surrounds the suction opening 127, is used. In this cross-section, in the vacuum pump 1, a distance sleeve 118 which is provided between the pump stages and spaces their components, and the last stator disc 117 of the high-vacuum pump stage 168 can be seen. A connecting screw 151 secures a retaining angle 150 to the chamber flange. A first expansion member 152 and a second expansion member 153 are arranged between the retaining angle and the pump flange.

FIG. 11 shows an associated cross-sectional view along line II-II′ in FIG. 10 and parallel to the shaft 111. It can be seen that a portion of the retaining angle 150, the first expansion member 152 and the second expansion member 153, and a portion of the pump flange 110 lay in a common plane. The first expansion member 152 has a wedge surface 158′ and the second expansion member has a wedge surface 158. The wedge surfaces 158 and 158′ are so contact each other that their displacement relative to each other becomes possible. The displacement is effected by a force-applying screw 155 that extends through a through-bore in an arm 154 of the first expansion member, with its threaded part engaging in the thread of the second expansion member 153. By tightening the screw, a planar force is produced that displaces the expansion members 152, 153 relative to each other. The action of the wedge surfaces converts the force direction in an axial direction. As a result, an axial press-on force 160 is produced in the operating point 159 and that presses the pump flange 110 and the chamber flange 120 against each other and that provides, thus, for a vacuum-tight connection. The expansion members 152, 153 provide for force direction conversion. Mounting and dismounting of the vacuum pump 1 is achieved by tightening and loosening the screw 155.

The expansion member 152, 153 insure transmission of a force from an application point 156 to the operating point 159 in the force transmitting structure 165. The force transmission enables to produce a press-on force at points which are not accessible as a result of the vacuum pump 1 being surrounded by components described with reference to FIG. 9. Advantageously, in this embodiment, in addition to force transmission, force distribution over the pump flange takes place, so that a uniform pressure is achieved. With an appropriate number of the wedge surfaces and their angles, the force distribution of the applied force over the flange 110 can be adjusted.

Because the housing 2 and the placed-on housing part 10 have the same outer profile, as shown in FIG. 4, the vacuum pump 1 can be mounted in an arrangement shown in FIG. 9 without any problem. As described with reference to FIGS. 10 and 11, the vacuum pump is fixedly secured in the arrangement. With the placed-on housing part 10 it becomes possible to meet customized requirements economically and without problem, as shown in the arrangement of FIG. 9.

Though the present invention was shown and described with references to the preferred embodiments, those are merely illustrative of the present invention and is not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is, therefore, not intended that the present invention be limited to the disclosed embodiments or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims. 

What is claimed is:
 1. A vacuum pump, comprising a housing (2) having an axial inlet (7); a pumping unit including a stator (5), a rotor (3) rotatably supported in the stator, and a drive (114) for driving the rotor; and at least one additional placed-on housing part (10) attachable to the housing (2) in an axial direction, connectable with the housing, and having at least one outlet (12).
 2. A vacuum pump according to claim 1, wherein the at least one housing part (10) has at least one radial inlet (11).
 3. A vacuum pump according to claim 2, wherein the at least one radial inlet (11) is provided at an end of the placed-on housing part (10) remote from the drive.
 4. A vacuum pump according to claim 1, wherein the housing (2) of the vacuum pump (1) has at least one radial inlet (8, 9).
 5. A vacuum pump according to claim 1, wherein the at least one placed-on housing part (10) has a same outer profile as the housing (2).
 6. A vacuum pump according to claim 1, wherein pump-active elements of the pumping unit are at least partially located in the at least one placed-on housing part (10).
 7. A vacuum pump according to claim 1, wherein the at least one placed on housing part (10) is free of the pump-active elements of the pumping unit.
 8. A vacuum pump according to claim 1, wherein the housing (2) and the at least one placed-on component (10) have a total length (L) of at least 550 mm.
 9. A vacuum pump according to claim 1, wherein the housing (2) and the at least one placed-on component (10) have a total length (L) of at least 700 mm.
 10. A vacuum pump according to claim 1, wherein the inlet (7) of the housing (2) and the outlet (12) of the at least one placed-on housing part overlay each other.
 11. A vacuum pump according to claim 1, wherein at least one of thermal sealing element, vibration-isolation sealing element, and electrical sealing element (21, 22) is provided between the housing (2) of the vacuum pump (1) and the at least placed-on housing part (10).
 12. A vacuum pump according to claim 1, wherein the vacuum pump (1) comprises at least one of turbomolecular pump stages and Holweck pump stages.
 13. A vacuum pump according to claim 1, wherein the vacuum pump has at least two inlets (8, 9, 11).
 14. An arrangement comprising a vacuum pump including a housing (2) having an axial inlet (7), a pumping unit having a stator (5), a rotor (3) rotatably supported in the stator, and a drive (114) for driving the rotor, and a pump flange; a chamber (102) having a chamber flange; means for vacuum-tightly connecting the vacuum pump and the chamber and including the pump flange and the chamber flange; wherein the vacuum pump further includes at least one additional placed-on housing part (10) attachable to the housing (2) in an axial direction, connectable with the housing, and having at least one outlet (12) and at least one radial inlet (11) connectable with the chamber (102).
 15. An arrangement according to claim 14, wherein the chamber (102) comprises a plurality of different chambers (121, 122, 123, 166), and the at least one radial inlet (11) is connected with at least one of the different chambers (166).
 16. An arrangement according to claim 14, wherein the arrangement further comprises a force-transmitting structure (165) for transmitting force from an application point (156) to at least one operating point provided on the connecting means.
 17. An arrangement according to claim 14, further comprising a mass-spectrometer (124).
 18. An arrangement according to claim 14, wherein the arrangement comprises a receiver, and the housing of the vacuum pump and at least one placed-on housing part have an outer profile adapted to a receiver profile. 